AspectS is an aspect-oriented extension to Squeak.

It is a prototype to support the exploration of AOP in dynamic 
environments like Squeak.  It mainly draws on the results of two 
projects: the first is AspectJ from Xerox PARC, a general-purpose 
aspect-oriented language extension to Java, and the second is John 
Brant's MethodWrappers, a powerful mechanism to add behavior to a 
compiled Smalltalk method.   In its current version, AspectS is
implemented in regular Squeak, without extending neither Squeak's 
syntax nor its virtual machine.

I have uploaded the current change set to:
http://www.prakinf.tu-ilmenau.de/~hirsch/Projects/Squeak/AspectS/

Also, there is 3.1alpha image pre-loaded with AspectS 0.1.0 here:
http://www.prakinf.tu-ilmenau.de/~hirsch/Projects/Squeak/AspectS/Old/AspectS-001-0013.zip
http://www.prakinf.tu-ilmenau.de/~hirsch/Projects/Squeak/AspectS/Old/AspectS-001-0013.tar.gz

I would like to invite anybody who is interested in working with 
me on AspectS, or another, better approach to explore AOP in Squeak.

Best,
-Robert

"PS:" Documentation is on the way. I will put an updated paper
      on my website anytime soon ...